Corrosion behavior of anodized nanoporous TiO2 films in oxidizing environments: a study on electrochemically engineered titanium surfaces

Abstract

This study presents a systematic investigation into the fabrication and corrosion behavior of nanoporous titanium dioxide (TiO₂) films formed via electrochemical anodization. Optimized anodization parameters, including electrolyte composition, applied voltage, and processing duration, yielded uniform nanoporous TiO₂ layers with pore diameters of 60–70 nm and thicknesses of 2–3 μm. Structural and compositional analyses using SEM, EDS, and XRD confirmed the formation of a well-ordered anatase TiO₂ phase. Post-anodization annealing further enhanced oxide purity by eliminating residual fluorides, as evidenced by XPS depth profiling. Electrochemical characterization in 25 mM Na₂SO₄ with increasing H₂O₂ concentrations revealed significantly improved corrosion resistance of anodized Ti compared to untreated Ti. Despite the lower polarization resistance (R_p) observed in EIS, the anodized oxide exhibited stable passivation, reduced corrosion current densities, and favorable capacitive behavior, attributed to its porous morphology and chemical stability. These findings demonstrate that engineered nanoporous TiO₂ films offer robust corrosion protection in oxidizing environments, supporting their application in biomedical devices, catalytic systems, and advanced nuclear materials.